1. Field of the Invention
The present invention relates in general to transfer switches configured for use with portable electrical power generation devices, for powering traffic signals and the like, during periods of unavailability of utility line power.
2. Background
When the utility line power to an electrically powered and controlled traffic signal fails, it is imperative to arrange for an alternative power supply as quickly as possible, so that the traffic signal can resume operation. Otherwise, police officers typically must man the intersection where the non-functioning traffic signal is located, or else the motoring and pedestrian public is placed in danger from traffic through an uncontrolled intersection. Using police officers or other personnel not only is an inefficient use of manpower, but also can be dangerous to the individuals manning the intersection, as they typically must position themselves in the midst of traffic in order to be seen, to provide traffic control guidance.
Usually, the method of supplying auxiliary power comprises the placement of a small portable generator, usually powered by a gasoline internal combustion engine, next to the traffic signal control pedestal, and electrically connecting the power output connections of the generator to the power input connections of the traffic signal control pedestal.
However, simply breaking the hardwire connection between the traffic signal controller and the utility line, and making a hardwire connection directly between the generator output and the traffic signal controller input, is a time consuming, inefficient and inelegant solution. One cannot splice in the generator input without disconnecting the utility line, as failure to do so could result in the accidental driving of current back up the utility line, which could, in turn, result in utility equipment damage as well as grave personal injury.